Urbanized estuaries are well-documented to have elevated contaminant levels in sediments,
water and associated biota. The difficulty in making sound assessments of the distribution
and bioeffects of these contaminants comes from a lack of detailed understanding
of chemical and toxicological interactions in a very complex environment. Many contaminants
entering the estuarine environment are not routinely included in existing monitoring
programs because of the lack of robust analytical methods for their detection and
quantification. This means that any risk to estuarine biota or human consumers associated
with these unmeasured contaminants cannot be evaluated. The challenge for marine
environmental analytical chemistry is to develop methodologies to identify and quantify
these compounds, their degradation products, and biological metabolites as they
enter estuarine waters and are deposited in sediments and⁄or accumulate in
biota. In addition, the potential toxicity of many of the contaminants entering
estuarine environments has not been evaluated in resident biota. The toxicological
challenge will be to identify appropriate model estuarine organisms and develop
sensitive endpoints for study.
Most previous research efforts examining the effects of anthropogenic contamination
in urbanized estuaries has focused on persistent priority pollutants, such as trace
metals, pesticides, PCBs and
PAHs. Recently, concerns
have been raised about the fate and effects of pharmaceuticals and other emerging
contaminants of concern that are being released into coastal watersheds through
upland runoff from both urban and agricultural lands, sewage discharges, industrial
releases, and aquaculture. In some cases, these releases are pulsed, short-lived
events, but they may also be nearly constant for non-persistent chemicals due to
the nature of the various sources.
Initial work is underway on:
- Brominated flame retardants (PBDES);
- Commonly used biocides in antifouling paints (irgarol, diuron, Sea-nine 211, dichlofluanid,
chlorothalonil and TC MTB);
- Simvastatin, the active ingredient in the commonly prescribed lipid reducing drug,
Zocor®; and
- Evaluation of nuclear magnetic resonance-based metabonomics as a potential biomarker
of contaminant exposure.